Gardening for pollinators: Choosing smart plants to support pollinators
A diverse selection of plants, reduction of pesticide use and observant gardeners can help preserve bees and other pollinators in landscapes and gardens.
Pollinators, including birds, mammals, bees, flies, beetles, butterflies and moths, are essential to the environment and our food supply. Pollinating more than 85 percent of the world's flowering plants, they contribute globally to “life as we know it.” More than two-thirds of the world's crop species are dependent on pollination, with an annual estimated value of $18 to $27 billion in the United States alone. Pollinators are also necessary in most terrestrial ecosystems since their activities are ultimately responsible for the seeds and fruits that feed everything from songbirds to black bears.
Recent concerns about losses of pollinating insects have caused gardeners to wonder how to make positive contributions towards their conservation. Understanding habitat needs and food sources while adjusting our garden maintenance routine is a step forward in pollinator conservation.
One often thinks first of the honey bee as a pollinator, but over 400 species of native bees also live right here in Michigan. Native bees come in many shapes and sizes, but pound for pound, they do a lot of work! These creatures are often uniquely linked with native trees, shrubs and herbaceous plants, but will also work a widely diverse garden plant palette.
Beneficial insects also make up the world’s hardest working workforce by keeping detrimental insects in the garden in check. A diverse selection of plants, both native and non-native, judicious reduction of pesticide use and observant gardeners come together to create a strategy for preserving bees and other “good bugs” in our landscapes and gardens.
“Bee” intentional about plant selection
Pollinators are looking for two things when they forage in your garden. The nectar and pollen found in blooming plants provides them with carbohydrates and protein they need to thrive and produce their offspring.
Think about “staging” the menu of blooms in your garden from early spring through fall by planting a wide range of flowering plants. Plants that bloom very early or late in the season are often the most important food sources for pollinators – since there are not many other resources available during this time.
Many annuals and perennials can be encouraged to re-bloom with pruning and routine dead-heading, while other garden favorites have been bred for a more continuous bloom. Dense, double-petaled selections may not accommodate a pollinator since the nectar glands and pollen laden stamens are more difficult to locate. A plant that was bred to be sterile or contain no nectar will not benefit a pollinator at all. Also, plants that have been selected for their visual attractiveness to us such as roses and azaleas may also not be used by pollinators.
Choose woody and herbaceous plants that bloom during different times of the year and at different heights. Thoughtful selection and placement of herbs, bulbs and annuals will enrich the available sources of food for these insects throughout the season, not to mention enhance your enjoyment as well. Bees will forage on many types of flowering plants, but they especially love flowers that are purple, blue, white, yellow, mauve or violet. Using ultraviolet (UV) light, bees also see things in flowers that our eyes cannot which include patterns, colors and markings that enable the insect to pilot directly to a “landing pad” leading to the pollen source.
Providing a wide range of bloom sizes and shapes will also encourage these insects regardless of their size. Tubular-shaped flowers with an extended petal such as foxglove or Salvia allow bees to alight and then enter the bloom. Open flowers like our native iron weed will provide resources to many kinds of beneficial insects.
The earliest spring-blooming plants such as Pachysandra, rock cress and bugleweed buzz to life with insect activity when windy spring weather makes it difficult to navigate the canopy higher up. Also low to the ground, minor bulbs like Siberian squill, Punchkinia and Chinodoxa attract the tiniest of bee species. Perennial favorites such as bleeding heart, foxglove and Allium ‘Purple Sensation’ bring in the late-spring show audience and larger bees are often seen feeding on these beauties. Herbs like chives also will be very attractive to pollinators.
By the time spring unfolds with crabapples bursting into bloom, garden favorites including single peonies reveal their pollen-laden anthers and start receiving attention by bees. Many types of coral bells are attractive to bees and with new hybrids available, will have fresh bloom spikes emerging every couple of weeks. The dark-leaved Heuchera ‘Bella Notta’ was specifically bred for these continual blooming traits and it is not uncommon to see plants setting new blooms well into September.
Mid-season, traditional perennial border plants including sneezeweed, blazing star, Inula and globe thistle offer unlimited opportunities for many types of pollinators to forage. Coneflower is also visited prolifically by bees. Dead-heading sneezeweed, Rudbeckia and many other perennials will encourage new blooms to form, so even the mid-season bloomers may make a second appearance later in autumn.
Summer bulbs such as Allium christophii and Allium ‘Millenium’ add to the palette and stretch the season as well. Butterflies will be attracted to a wide variety of lilies in the garden.
Colorful annuals and herbs can really pack a punch with colors to please the human eye while providing a long season of bloom. Herbs such as borage are irresistible for many species of bees and hover flies. By choosing sunflowers that are branched and range in days-to-harvest by a week or so, you can provide fresh blooms of these bee magnets for a longer period of time. A tall, late-summer annual known as Tithonia starts blooming in early August and continues until frost. Butterflies, bees and hover flies covet these flaming-orange blooms. Several zinnia cultivars are rarely visited by bees, however some of the more open types and Zinnia ‘Benary Giant’ are top contenders in the annual garden. Other annuals such as tall salvia (Victoria blue or white), lantana and pentas add color and provide nectar and pollen for many bee species.
Trees and flowering shrubs, both native and non-native, play a huge role in supporting pollinators. Half-way through summer the American linden and Little Leaf Linden burst into bloom with sweetly scented panicles of yellow blooms tucked beneath their foliage. Button bush, a favorite for moist soil or at the edge of a wetland, and panicle hydrangeas, with their stately towers of blooms, have sterile and fertile blooms on the stalk. Many types of bees visit the blooms and are supported by these plants.
Sedum has to be one of the most diverse plant groups in the garden or landscape. From low-growing, colorful ground covers to the upright, stately ‘Autumn Joy’ sedum, their blossoms are intoxicating for many bees and flies. These late-season bloomers help extend the available pollen and nectar along with garden favorites including Japanese anemone and Rudbeckia ‘Autumn Sun.’
Putting it all together
Beyond planting the right plants, gardeners should be thinking more about judicial use of insecticides – that is, either not using them or finding “green” products, always following label directions and always making sure never to spray on open blooms. While dead-heading plants like sneezeweed encourages additional blooms, early dead-heading of Hosta blooms may rob the pollinators of a great lunch. Blooming coleus may be thought of as unsightly, but not to a bee. A member of the mint family, these small blooms are very attractive to bees. Perhaps it is more about the way we think of “tidiness” in the garden and we let some things go.
Lastly, for every gardener who loves their mulch, it is greatly beneficial to have patches of open ground in the garden for nesting. These can be tucked out of the way, and bees will find them.
For more information about protecting pollinators, view the Buzz About Pollinators webinar from Michigan State University Extension, or visit the Pollination page on MSU’s Native Plants and Ecosystem Services website.